Address Assignment Question

Steve Richardson steverich.nanog at
Mon Jun 20 12:13:11 UTC 2011

Hello NANOG,
I work for a medium-sized ISP with our own ARIN assignments (several /18 and
/19 netblocks) and I've got a question about a possibly dubious customer
request.  I know a lot of you have experience on a much grander scale than
myself, so I'm looking for some good advice.

We have a customer who, over the years, has amassed several small subnet
assignments from us for their colo.  They are an email marketer.  They have
requested these assignments in as many discontiguous netblocks as we can
manage.  They are now asking for more addresses (a /24s worth) in even more
discontiguous blocks.  What I'd like to know is whether there is a
legitimate use for so many addresses in discontiguous networks besides
spam?  I am trying my best to give them the benefit of the doubt here,
because they do work directly with Spamhaus to not be listed (I realize
reasons on both sides why this could be) and searches on Google and spam
newsgroups for their highest traffic email domains yield next to nothing,
given the amount of email they say they send out.  I strongly believe that
their given justification for so many addresses is not a good one (many
addresses on an MTA, off-chance one gets blocked, etc), especially now that
IPv4 addresses are becoming more of a scarce resource.  However, if they
*are* legitimate, which certainly is possible, are discontiguous networks a
common practice for even legit operators, as it's quite likely that even
legit email marketers will end up being blocked because someone accidentally
hit 'Spam' instead of 'Delete' in their AOL software?


Note:  I hate spammers as much as anyone out there, but I *do* know that not
everyone who sends out massive amounts of email is a spammer.  While it's
possible they don't deserve it, I'm trying to give my customer the benefit
of the doubt.

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